Problem: Khan.scratchpad.disable(); For every level Kevin completes in his favorite game, he earns $780$ points. Kevin already has $420$ points in the game and wants to end up with at least $3210$ points before he goes to bed. What is the minimum number of complete levels that Kevin needs to complete to reach his goal?
To solve this, let's set up an expression to show how many points Kevin will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Kevin wants to have at least $3210$ points before going to bed, we can set up an inequality. Number of points $\geq 3210$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3210$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 780 + 420 \geq 3210$ $ x \cdot 780 \geq 3210 - 420 $ $ x \cdot 780 \geq 2790 $ $x \geq \dfrac{2790}{780} \approx 3.58$ Since Kevin won't get points unless he completes the entire level, we round $3.58$ up to $4$ Kevin must complete at least 4 levels.